Chemistry and Physics. 323 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Properties of Methane. — In preparing pure " marsh gas," 

 Moissan has made use of crystallized aluminium carbide made 

 by heating aluminium with carbon in the electric furnace, then 

 dissolving the excess of aluminium by treatment with hydro- 

 chloric acid at 0°, washing with ice-water, dry alcohol and ether, 

 and drying in a vacuum. The aluminium carbide, thus purified, 

 was allowed to act upon water at ordinary temperature in order 

 to produce the methane gas. The gas was then liquefied and 

 solidified, and from the solid product pure gas was obtained for 

 experimental purposes. Eudiometric analysis, by explosion with 

 oxygen, and subsequent absorption of carbon dioxide, gave results 

 agreeing very closely with theory. The density, by direct weigh- 

 ing in comparison with air, was found to be # 5540 and "5554 as 

 the results of two determinations, which agree very closely with 

 the theoretical density, and are a little lower than that previously 

 found by Thomson and by Schlcesing (*558). When methane 

 was brought into a tube surrounded with liquid air, it solidified 

 at first in a transparent form, like glass; but after a few moments 

 it suddenly crystallized in white needles. It was found to melt 

 at —184° and to boil at —164°. It was found that methane 

 always has a mild, slightly alliaceous odor, which cannot be 

 attributed to impurities. Experiments showed that solid methane 

 is attacked by liquid fluorine at —187° with explosive violence, 

 similar to the action of solid fluorine upon liquid hj^drogen. This 

 is another case, therefore, where chemical affinity persists at very 

 low temperatures. — Comptes Pendus, cxl, 407. h. l. w. 



2. Silicide of Carbon in the Canon Piablo Meteorite. — The 

 fact that Moissan has found the substance commonly called car- 

 borundum in the residue obtained by dissolving 53 kg. of this 

 meteorite has already been noticed in this Journal. The first 

 announcement of this discovery was perhaps not entirely convinc- 

 ing, as it was based merely upon finding crystals exactly resem- 

 bling silicide of carbon. Further examination has enabled Mois- 

 san to show, after separating the minute crystals by means of a 

 heavy solution, that they possess the physical and chemical pro- 

 perties of the compound, and also that they are composed of sili- 

 con and carbon. There is now no doubt, therefore, that this 

 interesting compound, previously known only as a product of the 

 electric furnace, actually occurs in nature. — Comptes Pendus, cxl, 

 405. h. l. w. 



3. A New Process for Detecting Ammonia in Water. — Tkillot 

 and Turchet take 20 or 30 ccm of the water to be tested in a test- 

 tube, then add three drops of a ten per cent solution of potassium 

 iodide and two drops of a concentrated solution of an alkaline 

 hypochlorite (commercial Javel's solution). When ammonia is 



